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Moldy Mayhem

Compartments that reach beneath the waterline present a special challenge to boaters who like everything spick and span. Here are 3 weapons to help battle the ick

Black battery covered by mold in a boat compartment.

Compartments that are vented to the bilge can quickly become mold farms.  Photo: Lenny Rudow

Does it seem like it’s impossible to prevent mold and mildew from growing in a compartment that goes below the waterline and drains into the bilge? That’s because it is! Any area that drains to the bilge vents to the bilge, and that means it will remain moist on virtually any boat. There are, however, several measures you can take to minimize the muck and keep that compartment clean.

Wax is a weapon

In your never-ending war against mold and mildew, your number-one weapon is wax. No, wax won’t prevent this stuff from forming. What it will do is make it über-easy to wipe those offensive black dots away with nothing more than a rag. Each and every gelcoated surface should be treated to a healthy dose of thick paste wax at the beginning of the season, and then every week or so you can swipe away that ick with ease.

Defensive liners

You may have noticed that the worst of the problem arises where something has been stowed in a compartment. That’s because air can’t circulate underneath that gear bag or tacklebox. By adding a liner that doesn’t trap moisture, however, you can ensure airflow across all the compartment’s surfaces. These liners come in mesh- and grate-like forms, and many can be puzzle-pieced together or cut with a pair of shears to fit oddly shaped compartments.

Three photos consisting of mold in a white storage compartment, a hand pulling back a black liner and a green Mold Armor spray.

Clockwise from left: You can see the beginning stages of mold growth, but because this compartment has been recently waxed, it will wipe away easily with a rag. Go on the offensive with a mold retardant. Adding a liner to the compartment will improve airflow and reduce the ick. Photos: Lenny Rudow, Mold Armor 

Militaristic mold retardants

Now that we have our defenses built, it’s time to go on the offensive with a mold retardant. Spray- or wipe-on mold retardants kill fungal spores and inhibit future growth. Apply this directly to the compartment’s surfaces and also douse the compartment liners and the undersides of hatches. There are plenty of these on the market to choose from, but note that most have a limited time span of effectiveness. Usually they’ll protect for up to about 90 days, so be prepared to reapply the retardant every few months.

Will employing all three of these armaments vanquish every speck of mold and mildew in those below-the-waterline compartments forever? Heck no. This is an ongoing battle all boaters must fight as long as they own a boat, lest that icky stuff grow out of control. But you can slow its intrusion to a creep by minimizing belowdecks moisture, giving those compartments regular cleanings, and staying on the attack with these three tactics.

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Author

Lenny Rudow

New Boats, Fishing & Electronics Editor, BoatUS Magazine

Top tech writer and accomplished sports fisherman, BoatUS Magazine Contributing Editor Lenny Rudow has written seven practical boating books, won 30 awards from Boating Writers International — many for his marine electronics articles – and two for excellence from the Outdoor Writers Association of America. He judges the NMMA Innovation Awards, and is Angler in Chief at FishTalk, his own Chesapeake-based publication. A great teacher and inspirational writer, Lenny hosts many of BoatUS Magazine’s very-popular how-to videos, which can be found on the BoatUS YouTube channel, or at BoatUS.com